Grinding mill, etc.



P. T. LlNDHARD. GRINDING MILL, ETC.

APPLICATION man JuLYzo. |921.

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Patented Dec. 5, 1922 mu-whwmu-\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ Patented Dec. 5, 1922.

nir-ED sTMa-s PrfrlaNT OFFICE.

rovL fr. LINDHARD, or BROOKLYN, Nnw Yoan, Assioma 'ro r. L. snIDTH e co., or

NEW `lYORK, N. Y., A CORPORATION OF NEW JERSEY.

j I .enmnme Application filed July 20,

To aZZ whom-it may concern.'

Beit known that I, PovL T. 'LINDHARD, a citizen of the United States, residing in theborough of Brooklyn of the city of New York, in the State of New York, have invented gairtain new and useful improvements in Grinding Mills, Etc., of. which the following is a specification, reference being had to the accompanying drawings, forming a part hereof. rlhis invention has been developed with particular reference to the improvement of the operation of grinding mills, in Vwhich the material operated-upon is subjected to the action of balls or other grinding bodies employed in successive chambers within a shell or drum which is rotated on a substantially horizontal axis, and in which the lmaterial operated upon by the grinding-.bodies is also subjected, in its passage from one chamber to another,'to a screening o eration, the material rejected by the screen eing returned to the preceding chamber for further reduction, while the screened material passes on to the succeeding chamber wherein it is further reduced by` other grinding bodies of diderent characteristics. it will nevertheless be understood that the improvements herein described, although designed for use in such a mill and for joint operation, are capable of use'independently and inj'mills or a paratus of a different character. Thus, whi e one part of the invention in designed to provide a relatively great screening'surface within 'a comparatively restricted space between two successive chambers of a grinding mill, it will be obvious that the improvements in the screening devices are capable of use independently of Aany grinding devices, as when the sole or chief purpose is the screening or separation of certain substances. So also the other main part of the invention, which relates' to the changing of the volumetric capacities of successive grinding-l chambers, so as to suit the requirements of different materials and different conditions of operation, although designed primarily for the improvement of such a millas that illustratedA and of which the improvedy screening devices or separators form a part, is nevertheless capable of application in connection with other screening devices-orsepal rators and in mills or apparatus of a diii'erent character. The. invention will be explained more fully hereinafter with reference to tht?A vhorizontal axis.

MILL, nrc. v

1921. seria; No. 483,993.

1y the means for securing a'partition inadjusted position Figure 4r is a detail viewvin section on the plane indicated by the broken line 4.-4 of Figure 3, looking' 1n the direction of the arrows.

In the structure shown in the drawing, which may be of usual or preferred construction except as hereinafter indicated, the gen-` erally cylindrical shell a, having a linin b, is provided at'one end with an inlet hea @and at the other endwith a discharge head d, and is mounted to rotate o'n a substantially In this mill are shown two successive grinding chambers, a primary grinding chamber c and a secondary grinding chamber f separated, .in this instance by an intermediate screening or se arating compartment g, which is itself capa le of adjustment, either as in its own length or in position as a whole-or in part, for the purpose of varying the relative volumetric capacities of the chambers e and f, as maybe required by the conditions of operation of the mill or ap aratus. Such variation in the relative vo umetric capacities of the chambers e and f might be effected without the employment of ascreening or separatin compartment, such as that illustrated, as y the employment of a partition which, in the construction shown, forms one end of the separatingI compartment and is itself adjustable or movable longitudinally within the shell a.

As shown such adustable partition comprises a plate k whic may be provided near its peri hery with apertures 71.', through which t e partially reduced material may pass from one side to the other of the partition while the grinding `bodies and the coarser material are retained in the primary grinding chamber. The 'corres ending partition plats' z,"at the other e ci' the sepsthe drum, is directed through the central l wall n2,

opening of a co-operating partition plate 7c. rlhe latter is provided with radial ribs lo', the extremities 71:2 of which, spaced from the lin' b of the shell, are inclined, as shown clear y in Figure 3, to form wedge surfaces. Arranged for cooperation with each radlal rib lo is a wedge block Z which at one side is formed with a convex shoe Z to conform to 'the inner surface of the lining b of the shell and at its other edge is inclined and grooved, as at lz, to co-operate with the wedge surface k2 of the rib. By means of a bolt m passed loosely through the Wedge block and through the plate lo, the wedge block may be drawn toward the plate lo and thereby be forced outwardly to press firmly against the lining b of the shell a and so secure the partition plate lo in adjusted position. The plate z is loosely secured to the wedge blocks Z so as to be held in position thereby, while permitting the necessary radial movement of the wedge blocks. By the means thus described, the partition formed of the plates h, lc or the partition formed of the plates h2, la, orA both of them, can be released from the shell and its lining, shifted longitudinally to permit such variation as may be desired in the volumetric capacities of the chambers e and f and, in the structure shown, the length of the separating chamber, and can then be secured firmly in adjusted position.

In the structure'shown there are two parf titions, one at each end of the separating chamber g. For the purpose of provi-ding within a comparatively., short space a great separating or screening surface, the separating compartment c comprises a series of intercommunicating separators n which are supported by the partition plates 7c and k2 and by each other, each separator consisting of an annular cage arranged transversely in the shell and having annular side walls` n, perforated to form screens, and a peripheral which may be imperforate, and, in

Athe construction shown, is spaced from the lining of the shell. At the inner edge of the annular side walls is an opening n3 to admit into the screening space the material under treatment and, in the revolution .of the shell,

to discharge for further treatment the coarse material which does not pass through the screens. As shown, each side wall is spaced from the adjacent side wall with which it forms a pair, or from the adjacent partition plate, whereby each perforated wall is unobstructed and there is formed a space through which vthe screened material may pass from the separators, in a general radial Lacasse the shell, the screened material is caused to travel onward until it is discharged into Ythe succeeding chamber f. It will be noted that the perforated side walls n are annular only, having large central openings, so that together they form intercommunicating separators from one to the other of which, throughout the series, the material which has not been reduced to such a degree of fineness as to pass through the perforated an# nular walls, may pass on until it is so reduced. These side. walls are not extended entirely across the separating chamber, for if so extended they would form between them separate grinding compartments and would prevent the accomplishment of the main purpose of this invention, namely, to provide great. screen surface within a limited space, the accomplishment of this purpose being possible only with annular transverse screens with provision for the passage of coarse material over each screen into the next separator compartment. As indicated in Figures 1 and 2, the separator compa-rtments may each be formed for convenience in circumferential sections and the several separators be bolted to each other and to the adjacent partition plates. The arrangement of the screens transversely with respect to the axis of the shell with spaces at the outer screen faces through which the screened material may be discharged, makes it possible to provide great screen surface within a limited space and so enables the production to be increased greatly as compared with screening devices heretofore employed.

It will be obvious not only that the area of screeningsurface can be varied at will by adding or removing separator units between the movable end walls or partition plates, but that the relative volumetric capacities oi the chambers e and f can be varied at will, either by shifting the separator compartment as a whole toward one end or the other or by adding or .removing a separator unit at one end or the other of the separator com partment. In this manner the maximum efficiency of the apparatus can be attained with materials and grinding bodies of different characteristics.

It will be understood that various changes in details of construction and arrangement can be made to suit different conditions of use and that, except as pointed out in the claims, the invention is not restricted to the precise construction shown and described herein.

Alll) wall and two annular perforated side walls having an opening between their inner edges to, admit into the screeningk space the material under treatment and to discharge the coarse material, the faces of both side walls being unobstructed so as to permit the screened material to pass. outward through. both side walls.' v

2. A rotary separator comprising a series of intercommunicating separator units, each separator unit having a peripheral wall and an annular perforated side wall with `an opening at its inner edge to admit into the screening space the material under treatment and to discharge the coarse material, the faces of the several side wallsbeing unobstructed so as to permit the passage of the material'through' said side walls.

3. A rotary separator comprising'a series of transverse annularv screens, said screens being arranged 1n serles to form lntercommunlcating separator compartments spaced from each other to' permit the screened material to pass from. adjacent compartments into the space between, and means to receive the screened material from such intermediate spaces. I

' 4. A of transverse annular screens, said screens being arranged in series to form intercommunicating separator compartments spaced from each other toV permit the screened material to pass from adjacent compartments',

into the space betweenl andmeans to receive the screened material from such intermediate spaces and convey it in a -longitudinal direction. u l

5. The combination of a rotating shell, and a series `of annular separator units supported rotary separator comprising a` series therein and spaced interiorly from the shell v passage of the screened material and con- .veyor ribs in the space between the separator units and the shell.

7. The combination of a shell, a transverse partition plate provided with longitudinally movable wedge surfaces, wedge blocks arranged to co-operate with the we d e surfaces and to bear against the shell, an means to nilofe the Wedge blocks longitudinally in the s el.

8. The combination of a shell, a transverse partition plate having radial ribs forming wedge surfaces at their extremities, wedge blocks to co-operatev with the wedge surfaces and to bear against the interior of the shell, and bolts to draw the wedge blocks on the wedge surfaces toward the'partition plate.

9, The combination of a rotating shell, a

separator composed of a series of independent, detachable separator units, and means to secure the separator within the shell.

This-sgecification signed this 15th day of July A. 1921.

l* rovL r. LINDHARD. 

